1. Field of the Invention
The present invention relates to a structure having an outer wall system, the construction of which provides for flow of air between an internal wall section and an external wall section for inhibiting moisture accumulation and mold growth on the internal wall section.
2. Description of the Related Art
In today's construction industry, numerous residential structures, and even a significant number of commercial structures such as, for example, apartment buildings, motels, restaurants, and strip shopping centers, have their exterior surfaces finished with a synthetic stucco-type coating applied over a foam insulation board. Such exterior finishes are generically referred to as Exterior Insulation and Finish Systems, and will be referred to hereinafter as EIFS.
While such EIFS constructions have proved to be quite satisfactory for their relative ease of installation, their insulating properties, and their ability to receive a variety of aesthetically-pleasing finishes, a serious problem associated with EIFS construction exists. This problem is one of moisture accumulation behind the exterior wall covering. As used herein, the term “moisture” refers to both liquid and airborne forms of water, including condensation. Such moisture may be the result of condensation or high humidity, but may also be the result of wind-driven water, that may enter behind the exterior wall covering at any point where the exterior surface of the coating is penetrated. Such moisture accumulation may be the result of poor workmanship or design, deterioration of flashing or sealants over time, lesser quality doors or windows, or any other penetration or compromise of the exterior finish.
When such water penetration, high humidity, or condensation occurs, absent effective, reliable means for eliminating the moisture from behind the EIFS exterior construction, the moisture can remain trapped long enough before evaporating to damage or rot any moisture-sensitive elements to which the insulation is bonded, typically wood framing, oriented-strand board, plywood, or gypsum sheathing. In addition, the moist environment is a breeding ground for wood consuming insects and health hazards such as various varieties of molds. This problem is accelerated in hot and humid environments.
Attempts have been made to prevent entry of moisture into the building wall interior by sealing or caulking entry points in and around wall components as the primary defense against moisture intrusion, or by installing flashing around the wall components to divert the moisture. These attempts have not been completely successful. Sealants are not only difficult to properly install, but tend to deteriorate and separate from the wall component or wall due to climatic conditions, building movement, the surface type, or chemical reactions. Flashing is also difficult to install and may tend to hold the moisture against the wall component, accelerating the decay.
The use of sealants and flashing is also limited to the attempted minimization of moisture collection in building walls in new construction, and the further collection in existing structures. These materials are of no value in addressing the problem of moisture that has already entered a building wall interior. Thus, with solutions presented in the prior art, moisture still enters the wall interior, and the problem is further compounded by the prevention of any evaporation of the moisture already in the wall interior.
The problems of moisture penetration and accumulation have prevented the full use of new building cladding materials, and has resulted in many buildings with rotting framing structures, requiring extensive and expensive retrofitting. Thus, there is a great need for an system and method to prevent moisture from accumulating in the wall interior of a building at wall components, and for the removal of moisture that has already collected within the wall interior.